You have to look at the reason why you need consent to determine if there's a problem. If your ESIGN consent and service agreement relates only to monthly statments for jointly held deposit accounts, for example, then you only need valid ESIGN consent from one of the depositors. Neither Regs E or DD require delivery of periodic statement disclosures to both parties.
If both parties ARE entitled to separate account disclosures (for example, each has an account in her/his individual name), then you have an operational issue, as Randy said.
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...gone fishing.